银屑病表观遗传调控研究进展

银屑病是一种慢性炎症性增生性疾病,受到基因及环境等多种复杂因素的作用。其中包括表观遗传学,表观遗传可在不影响DNA序列改变的前提下,引起基因表达的稳定可遗传的改变,涉及DNA甲基化、非编码RNA调控、组蛋白修饰、基因印迹、x染色体失活等。银屑病患者具有明显的甲基化修饰异常,可致相应调控基因表达增多或减少;非编码RNA也可作用于相应靶点影响有关因子合成;组蛋白修饰异常参与银屑病角质形成细胞增殖异常。     

Permanent and plastic epigenesis in neuroendocrine systems

The emerging area of neuroepigenetics has been linked to numerous mental health illnesses. Importantly, a large portion of what we know about early gene × environment interactions comes from examining epigenetic modifications of neuroendocrine systems. This review will highlight how neuroepigenetic mechanisms during brain development program lasting differences in neuroendocrine systems and how other neuroepigenetic processes remain plastic, even within the adult brain. As epigenetic mechanisms can either be stable or plastic, elucidating the mechanisms involved in reversing these processes could aid in understanding how to reverse pathological epigenetic programming.     

Optimizing nonviral-mediated transfection of human intervertebral disc chondrocytes

BACKGROUND CONTEXT: The use of viral vectors for transfection of human disc chondrocytes has been well documented. However, because of immunological and cell toxicity concerns, nonviral reagents may provide gene delivery to intervertebral disc (IVD) chondrocytes without these associated obstacles. Several studies have been done using nonviral delivery systems with varying degrees of success. PURPOSE: The purpose of the study was to determine the efficiency, toxicity, and optimal conditions for gene delivery into human degenerative IVD cells via nonviral reagents in vitro. STUDY DESIGN/SETTING: In vitro viral and nonviral gene transfer. PATIENT SAMPLE: Human disc chondrocytes from 21 patients undergoing discectomy for trauma, disc herniation, and fusion for scoliosis or degenerative low back pain. OUTCOME MEASURES: Cell cytotoxicity and transfection efficiency as determined by microscopy, luciferase assay, and flow cytometry. METHODS: Seventeen lipid-based nonviral reagents coupled to DNA plasmids coding for luciferase were transfected into cultured chondrocytes. Cells were transfected with varying ratios of DNA plasmid to reagent, harvested at 48 hours and analyzed for transfection rates and cell viability. Transfections with adenoviral constructs were comparisons. The three most efficient reagents were then coupled to green fluorescent protein and the experiments repeated. The most efficient reagent after these experiments (LT1) was tested in standard chondrocyte-maintenance medium and a minimal medium mixture devoid of antibiotics, buffers, and amino acids. Finally, LT1 in minimal medium with various hyaluronidase treatments was tested. The most effective reagents and relative toxicity as measured by flow cytometry were analyzed using repeated measures analysis of variance. RESULTS: LT1 was most efficient and least toxic of nonviral reagents tested. LT1 had a mean percent survival of 78.1% versus 26.6% for TKO, 15.8% for T-Jurkat, and 70.8% in controls. Transfection was 1.5%. LT1 in minimal medium was significantly better than other reagents for both cell viability and transfection percentages. Minimal medium increased transfection with other reagents, yet cell viability with TKO and T-Jurkat was poor. Hyaluronidase had no effect on the viability of controls and decreased viability from 74.9% to an overall mean of 62.6% for all treatments. Transfection percentages increased from 1.8% without treatment to 15.2% with 40 units and 10.4% with four units of hyaluronidase given 24 hours before transfection and left in throughout the experiment. When treated at the time of transfection, efficiency was not significantly different to samples without hyaluronidase added. Additionally, hyaluronidase added 24 hours before transfection and washed out at the time of transfection significantly increased transfection percentages. CONCLUSIONS: LT1 was the most efficient reagent in terms of transfection ability and cell toxicity compared with other reagents. Treatments in minimal medium yielded significant increases in transfection and no significant difference in toxicity as compared with controls. Hyaluronidase treatments improve transfection significantly but also increase toxicity. These results suggest that the nonviral reagent LT1 can be used to transfect IVD chondrocytes in vitro and may help facilitate gene transfection of IVD chondrocytes in vivo.     

肿瘤发生的表观遗传学:进展与临床意义

表观遗传(epigenetics)指所有不通过DNA序列改变就能影响基因表达(从而决定细胞乃至个体表型)的、可遗传的(即可伴随细胞分裂传递下去)调控方式,包括DNA甲基化、组蛋白修饰、染色质重塑、miRNA、朊病毒等。表观遗传调控在干细胞自我更新、定向分化、器官发育等生命过程中起着至关重要的作用:每一个多细胞生物个体都是由一个受精     

Cocaine-induced metabolic activation in cortico-limbic circuitry is increased after exposure to the histone deacetylase inhibitor,sodium butyrate

Drug-induced inhibition of histone deacetylase (HDAC) results in the modification of many behavioral changes resulting from exposure to cocaine and other stimulant drugs-of-abuse, but a comprehensive map of the neuronal circuitries involved is lacking. The present study used blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD fMRI) in awake rats to determine the effects of the HDAC inhibitor, sodium butyrate (SBt) on brain metabolic activation patterns during the initial stage of repeated cocaine administration. Three groups of rats received cocaine during BOLD fMRI, (i) acutely for the first time, or pretreated for 2 days with either (ii) saline or (iii) SBt 30 min prior to cocaine. Acute but not repeated exposure to cocaine resulted in widespread BOLD activation in fore- and mid-brain. Pretreatment with SBt restored BOLD signals in the forebrain after repeated cocaine exposure, including a pronounced activation in the anterior thalamus, the hippocampus/amygdala and various portions of limbic and sensory cortex. Mesocorticolimbic areas showed a similar trend, but did not reach statistical significance. These findings suggest that HDACi modulation after repeated stimulant exposure involves cortico-limbic circuitry regulating emotion, motivation and memory.     

A comparison of the effect of lead nitrate on rat liver chromatin, DNA and histone proteins in solution

Although lead is widely recognized as a toxic substance in the environment and directly damage DNA, no studies are available on lead interaction with chromatin and histone proteins. In this work, we have examined the effect of lead nitrate on EDTA-soluble chromatin (SE chromatin), DNA and histones in solution using absorption and fluorescence spectroscopy, thermal denaturation and gel electrophoresis techniques. The results demonstrate that lead nitrate binds with higher affinity to chromatin than to DNA and produces an insoluble complex as monitored at 400 nm. Binding of lead to DNA decreases its Tm, increases its fluorescence intensity and exhibits hypochromicity at 210 nm which reveal that both DNA bases and the backbone participate in the lead–DNA interaction. Lead also binds strongly to histone proteins in the absence of DNA. The results suggest that although lead destabilizes DNA structure, in the chromatin, the binding of lead introduces some sort of compaction and aggregation, and the histone proteins play a key role in this aspect. This chromatin condensation, upon lead exposure, in turn may decrease fidelity of DNA, and inhibits DNA and RNA synthesis, the process that introduces lead toxicity at the chromatin level.     

组蛋白甲基化水平与骨关节炎病理发展的关联性

骨关节炎是最常见的软骨退行性疾病。越来越多的研究显示，表观遗传学与骨关节炎之间密切相关，表观遗传修饰方式组蛋白甲基化水平与骨关节炎相关。组蛋白H3上不同氨基酸甲基化水平与骨关节炎病理发展的关联具体表现为第4位赖氨酸甲基化水平上升将加剧骨关节炎病理发展，而第9位与27位赖氨酸则呈现相反现象。因此，组蛋白甲基化修饰存在复杂网络，如能针对不同位置组蛋白的甲基化水平进行特异性靶向调控，有望延缓或阻止骨关节炎的发展。     

乳腺癌中组蛋白乙酰化与p21^WAF1的表达研究

目的探讨乳腺癌中乙酰化的组蛋白H3、H4及p21^WAF1的表达变化及其意义。方法采用HE染色鉴定乳腺癌的病理形态变化;应用免疫组织化学法检测p21^WAF1在80例乳腺癌组织与80例正常乳腺组织中的表达;免疫印迹法检测乙酰化的组蛋白H3、H4及p21^WAF1蛋自在80例乳腺癌组织及80例正常乳腺组织中的表达。结果·HE染色可见,与正常的乳腺组织相比,乳腺癌组织结构及细胞形态有明显的异型性。免疫组化结果显示：p21^WAF1。在80例乳腺癌组织中有49例阳性表达（61．25％）;而80例正常乳腺组织中只有3例弱阳性表达（3．75％）,两种组织中的表达差异有统计学意义（P〈0．05）。免疫印迹法结果表明,p21^WAF1蛋白在乳腺癌中的表达高于正常组织,乳腺癌组为0．78±0．095、正常乳腺组为0．65±0．055;乙酰化的组蛋白H3、H4在正常乳腺组织中的表达比乳腺癌组织高,其中乙酰化的组蛋白H3正常乳腺组为2．35±0．340、乳腺癌组为1．07±0．067,乙酰化的组蛋白H4正常乳腺组为3．44±0．202、乳腺癌组为1．11±0．086,两者表达差异均有统计学意义（P〈0．01）。结论组蛋白乙酰化与p21^WAF1蛋白的表达变化与乳腺癌的发生发展有关。